/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.util;

import proguard.classfile.*;

/**
 * An <code>ExternalTypeEnumeration</code> provides an enumeration of all types listed in a given external descriptor
 * string. The method name can be retrieved separately.
 * <p>
 * A <code>ExternalTypeEnumeration</code> object can be reused for processing different subsequent descriptors, by means
 * of the <code>setDescriptor</code> method.
 *
 * @author Eric Lafortune
 */
public class ExternalTypeEnumeration {
    private String descriptor;
    private int index;

    public ExternalTypeEnumeration(String descriptor) {
        setDescriptor(descriptor);
    }

    ExternalTypeEnumeration() {}

    void setDescriptor(String descriptor) {
        this.descriptor = descriptor;

        reset();
    }

    public void reset() {
        index = descriptor.indexOf(JavaConstants.METHOD_ARGUMENTS_OPEN) + 1;

        if (index < 1) {
            throw new IllegalArgumentException("Missing opening parenthesis in descriptor [" + descriptor + "]");
        }
    }

    public boolean hasMoreTypes() {
        return index < descriptor.length() - 1;
    }

    public String nextType() {
        int startIndex = index;

        // Find the next separating comma.
        index = descriptor.indexOf(JavaConstants.METHOD_ARGUMENTS_SEPARATOR, startIndex);

        // Otherwise find the closing parenthesis.
        if (index < 0) {
            index = descriptor.indexOf(JavaConstants.METHOD_ARGUMENTS_CLOSE, startIndex);
            if (index < 0) {
                throw new IllegalArgumentException("Missing closing parenthesis in descriptor [" + descriptor + "]");
            }
        }

        return descriptor.substring(startIndex, index++).trim();
    }

    public String methodName() {
        return descriptor.substring(0, descriptor.indexOf(JavaConstants.METHOD_ARGUMENTS_OPEN)).trim();
    }
}
